Petrol in a Diesel Car in Segensworth: How Worried Should You Be?
If it has not been started, worry less than you probably are. Until the ignition primes the pump, your starter cranks, or the car is driven, petrol in a diesel tank just sits there and does nothing. Which makes the honest reply to the first Segensworth query — "have I wrecked it?" — normally no. Petrol in Diesel is who to phone, with your engine kept off, and so it stays that way. The remainder of this page covers what petrol really does to a diesel, how to tell how far it has got, and how to make sure it does not happen to you again.
Inside the engine: what petrol in a diesel does
Passing through an engine, diesel is doing two things at once. Before it combusts, it lubricates — and then it burns. Your high-pressure pump and the fuel injectors are built to extremely fine tolerances, and your diesel passing through them is what stops those surfaces from wearing against one another.
Petrol does the first job poorly and the second not at all. Being less viscous than diesel, petrol strips out the lubrication a fuel system needs, so a pump on the mixture wearing itself. It's also made to resist igniting under compression — the reverse of what a diesel needs — which is why you get the rattling.
Put those together and the shape of the issue is clear. It's movement that does the harm, not contact. All a tank with petrol in it amounts to is a fuel problem. Whatever a worn pump sheds travels on, borne by your fuel, into the fuel injectors downstream, which is why a pump that has worked on the petrol is where a mechanical problem begins.
How bad is petrol in a diesel? Four scenarios our engineers see in Segensworth
The best case there can be: filled up, never started. Being on a forecourt is what makes this possible: elsewhere, the vehicle has been driven there to begin with. With that petrol kept in the tank alone, it's cleared and flushed right where it stands, and nothing more is needed.
A brief spell of running, or merely the ignition on. Petrol has left that tank and reached the filter and your lines, since the system has been primed. That is normally still a simple task — a drain, a flush, and your filter dealt with.
Those few miles driven were your pump running on fuel thinned by petrol the whole way. Distance is only half of it; how hard it was driven matters just as much. Either way the work includes your tank, your lines, your filter and clean fuel through the entire system. On the school run to Cornerstone CofE (VA) Primary School, the distance is small. Very different a second time: a trip to Southampton, under 10 miles away, or some distance on the M27, under a mile from Segensworth, where the engine never stopped labouring hard.
Driven till it protested. Rattling, an uneven idle, smoke, a throttle that has gone soft. That's your motor telling you its fuel no longer is behaving like diesel. Whether it is the verge on Witherbed Lane, a lay-by or a side street, stop there then leave it. What comes first is still the fuel drain and flush, and that takes care of it, with permanent damage very rare if a vehicle is pulled over early.
Segensworth drivers and the petrol in a diesel stories they hear
"Top it up the rest of the way with diesel and it'll be fine" — a myth. It will not. A fuller tank of the same mix is all you get, because topping up takes out nothing. Percentage isn't how a diesel fuel system tolerates petrol, whatever that advice presumes.
Myth: "A current diesel can cope with a bit of petrol." If anything, the opposite. Smaller components and higher pressure are how a modern diesel runs its fuel, and that makes the protection count more, not less.
"It starts, it drives, so there is no harm" — the myth that trips up most motorists than any other. The driver of a petrol motor fed diesel usually stops, since it will not run, and the damage stops there. While the pump grinds, a diesel fed petrol usually starts, idles and drives away as if nothing has happened. Running is not the same as fine.
"A drop of two-stroke oil and drive it home" — a myth, taken from a fix from years ago, for a separate fault. What petrol has thinned stays diluted, and the petrol remains inside that tank regardless.
If the engine has run, part of that petrol is in the filter and your lines, not that tank — and the next start pulls it straight back through your pump. So the myth "drain your tank yourself and you are sorted" doesn't stand up. It's also really risky to drain petrol into a can by the roadside.
Petrol in a diesel: how does it happen?
Carelessness is rarely the cause, and no one means to do it. One way only, since of the nozzles: the smaller petrol one slips inside a diesel filler with almost no resistance, while the diesel one mostly will not fit a petrol vehicle. That is how the forecourt makes it simple.
The moment routine stops matching the vehicle is the moment it takes place. Courtesy car, hire car, or a car that is new. A household with one petrol and one diesel on the driveway. A familiar forecourt with the pumps in a different order. A train to catch, and a hurried fill on the way to Swanwick. The first fill-up in a diesel Renault Megane after years of driving petrol is precisely the moment it happens. Throw in a back seat full of children, a phone call or rain, and habit takes over.
Segensworth drivers: how to avoid petrol in a diesel next time
- Read the pump, not the colour. In the UK unleaded handles are usually green and diesel black, but not on every forecourt. The label is what counts.
- The first fill in a strange car is the time to check your filler flap — inside it, or on the cap, many vehicles state the fuel they take.
- A coloured fob or a sticker on the diesel's key achieves more than any amount of intending to remember, for a household with one of each.
- It sounds daft and it does the trick: on the first fill in a new or hired car, say "diesel" out loud before you lift the nozzle off the petrol pump.
- Put your phone away. This is an easy mistake to make while you are thinking about something else.
- Add-on devices are available for vehicles without one, and some diesels are built with a filler that will not accept a petrol nozzle. Useful — but a safety net only, never a reason to stop checking the label.
- The moment you realise, stop: less petrol inside that tank makes a thinner blend. What to do next does not change, though — still do not crank it.
Segensworth: already put petrol in a diesel?
Short and simple, then, is the order of things. Do not turn your ignition on, and don't fire it up. Ask the attendants to help you roll it away from the pump if you are still at the forecourt, whether that's BP or somewhere else. Then ring 0333 366 0103 and tell us what got in, roughly how much, and if it has run.
AdBlue, not petrol? Then say so. Corrosion and deposits, not lost lubrication, make it a separate fault — Segensworth has a page just for it.
Why one petrol in a diesel job around Segensworth costs more than another
An honest single price doesn't exist here: four scenarios, four separate tasks. The situation itself does most of the work of moving the cost. Two things come after that: the petrol that went in as a share of what your tank holds, then the spot the car is in and whether a technician can get to it safely.
Three queries come first, before quoting, instead of after — what went in, how much, has it run — and that is the reason. A range turns into a straight figure once those replies are in.
About Segensworth itself
Segensworth is a small village in Hampshire, situated near the coast and approximately 7 miles from Southampton. Segensworth has a population of around 1135 people and is characterised by predominantly detached housing. Segensworth sits at an elevation of 41 metres, close to nearby places such as Titchfield Park and Locks Heath. Segensworth is also within commuting distance of London, being around 65 miles from the capital.
Across Hampshire and around Segensworth: fuel drain cover
Petrol in diesel call-outs in Segensworth — part of the PO postcode area — go to vans that also cover the places about it, Titchfield Park, Park Gate and Locks Heath included. You need not bring your vehicle to us. Forecourts, supermarket car parks, lay-bys and your own drive are all places we drain.
Segensworth: still at the pump?
The best spot there is, then — that's where you are. Keep it off. Phone.